1 Reasons in the production process Whether or not the dark color masterbatch was produced the previous time, the machine has not been cleaned.
2 Reasons for raw materials The quality of ABS raw materials themselves and the impact of dust during storage and transportation. Take ABS particle raw materials, tablet, detect the number of black spots and diameter.
3 Environmental reasons Check that the workshop is clean; check for oil contamination under the pelletizer bearings.
4 Process conditions
a. Extrusion molding conditions Whether molding processing temperature within the specified range, the temperature is too high can easily cause carbonization of the material. Whether the screw speed is normal and the screw rotation speed is slow, the material residence time is long. On the contrary, when the screw rotation speed is fast, the material residence time is short, and the residence time will affect the color of the material. Whether the back pressure meets the requirements, the back pressure is too small, the residence time of the raw materials must be lengthened, and the extruding material is easily discolored.
b. Checking the die The die is too fine, debris accumulates, and material stagnates, all of which can easily cause dead deposits.
c. Check the mesh of the filter mesh is too fine, the material can not be extruded normally, resulting in the raw material flowing back, and there will be discoloration and charring.
d. Checking the feed tube After long-term use of the feed tube, carbon deposits may occur.
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2 Solution
1 Whenever dark pigments are produced, choose clean, relatively inexpensive, high temperature resistant, high viscosity resins, such as acrylonitrile-phenylene copolymers or acrylic resins, to clean the extruder, including die, feed tubes, etc. (The amount is at least one hundred kilograms), it can take away carbon and debris.
2 Regularly communicate with raw material suppliers and quality raw materials. And in the storage and transportation of raw materials, dust protection work.
3 Optimization of production process conditions
4 Clean the production workshop regularly to keep the workshop clean and hygienic. Make sure there is no oil under the pelletizer bearings during production.
5 Clean the die and tube regularly.
6 Replace the new filter regularly.
